Field of the Invention
Various embodiments of the present invention relate to an electronic semi-active mount, and, particularly, to an electronic indirect by-pass type semi-active mount realized in an indirect by-pass manner capable of increasing a dynamic characteristic change rate and to which a solenoid valve generating a small force compared to a vacuum negative pressure is applied, an electronic semi-active mount apparatus, and a method of controlling a dynamic characteristic variable rate thereof.
Description of Related Art
In general, a semi-active mount provided between an engine (or a power train) and a vehicle body effectively reduces vibration caused due to driving of the engine by ON/OFF controlling dynamic characteristics.
The semi-active mount (hereinafter, referred to as “SAC”) is classified into a vacuum negative pressure type SAC which controls an inner passage in a by-pass manner and an electronic SAC which controls an inner passage in a VS (Volume-Stiffness) manner by a solenoid valve. Considering performance, the vacuum negative pressure type SAC has an advantage of having good low frequency dynamic characteristics because of having a dynamic ratio of about 0.6 in a low frequency range (20˜40 Hz), compared to the electronic SAC having good high frequency dynamic characteristics. Accordingly, since the vacuum negative pressure type SAC is very advantageous to maximize idle performance of the engine, it is mainly applied to vehicles.
On the other hand, the vacuum negative pressure type SAC is supplied with a vacuum negative pressure from an intake manifold (or a gasoline engine) a vacuum tank (a diesel). For this reason, the vacuum negative pressure type SAC may cause disadvantages such as addition of parts by a vacuum hose, modification of parts due to application of a valve for vacuum negative pressure to the engine, and layout change of an engine room, and a combustion back pressure may be lost in the vacuum negative pressure type SAC.
To resolve problems of the vacuum negative pressure type SAC, there is used an electronic indirect by-pass type SAC (hereinafter, referred to as “EIBP_SAC”) which is an electronic SAC and indirectly realizes a BP (By-Pass) manner in a VS (Volume-Stiffness) manner.
The EIBP_SAC is provided with a secondary nozzle and a secondary diaphragm using the VS manner. A solenoid valve generating a small force compared to a vacuum negative pressure is opened or closed such that air outside the secondary diaphragm communicates or does not communicate with the atmosphere, thereby enabling a fluid flowing to the secondary nozzle to be controlled in the BP manner of the vacuum negative pressure type SAC.
Therefore, the EIBP_SAC may resolve problems in relation to an overall size, heating, and an amount of current due to opening or closing of the secondary nozzle using the solenoid valve by introducing the BP manner to the vacuum negative pressure type SAC. Particularly, since the EIBP_SAC uses electromagnetic force generated by the vehicle, the EIBP_SAC may realize simplification of a system and be applied to a different vehicle type, compared to the vacuum negative pressure type SAC.
However, the EIBP_SAC has a structure that the secondary diaphragm through which the outside air communicates or does not communicate with the atmosphere by the solenoid valve is not directly fixed and a primary diaphragm always communicates with the atmosphere. For this reason, when a fluid flowing to the secondary nozzle is controlled, the fluid simultaneously flows to a primary passage. Accordingly, since the EIBP_SAC has a low dynamic characteristic change rate due to the undesired flow of fluid in the primary passage, the EIBP_SAC may be more advantageous to maximize idle performance of the engine, compared to the vacuum negative pressure type SAC.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.